Background: There is a growing interest worldwide to identify novel functional foods able to exert important biochemical activities with low or without toxic effect. Accordingly, the use of Salvia hispanica L. (chia) a Mexican herb, has tremendously grown as an agriculture crop owing to the nutritional and medicinal values. The objective of this study was to evaluate phytochemical composition of chia seeds and prove their claim for functional properties. Materials and Methods: The determination of total phenolic, flavonoid and condensed tannin contents of chia seeds were carried out by the Folin-Ciocalteu, the aluminum trichloride and the vanilline acid spectrometric methods. Antioxidant activities of chia seeds extracts were assessed using free radical scavenging assay DPPH, Ferric Reducing Antioxidant Potential FRAP and β-Carotene bleaching assay. Results: Chia seeds contain high levels of total phenolic and flavonoid contents 19.06±0.14 mg GAE/ g DW and 12.3±0.04 mg CE/g DW, respectively. The content of condensed tannins was estimated at 8.32±0.01 mg CE/g DW. The flavonoid extract showed a higher antioxidant potential against DPPH, FRAP and the bleaching of β-Carotene (0.27±0.00, 0.06±0.03 and 0.39±0.01 mg/mL, respectively). Conclusion: Following the obtained results, we should explore the use of this seeds in food products due its nutritional and chemical composition, possible human health benefits and role as a functional food.